KF Listen Server not letting friends connect :(

I've portforwarded all the needed ports, and messed around with some killingfloor.ini settings, like uplinktogamespy to false, but I just can't get my friends to join my server. I've tried having them direct connect, using shift-tab on steam and just going to the friends tab on server browser.



If I could get any help it would be highly appreciated. :)